Bleach-fixing solution for color photography

ABSTRACT

A SINGLE BLEACH-FIXING SOLUTION FOR COLOR PHOTGRAPHIC LIGHT-SENSITIVE MATERIALS COMPRISING A FERRICYANIDE AND A THIOCYANATE AND CONTAINING AT LEAST ONE COMPOUND HAVING AN ALDEHYDE GROUP OR A METHYLOL GROUP IS DISCLOSED.

U measures Patent 01 ace 3,667,950 Patented June 6, 1972 3,667,950 BLEACH-FIXING SOLUTION FOR COLOR PHOTOGRAPHY Hiroyuki Amano, Haruhiko Iwano, and Kazuo Shrrasu, Kanagawa, Japan, assignors to Fuji Photo Film Co., Ltd., Kanagawa, Japan No Drawing. Filed Dec. 16, 1970, Ser. No. 98,881 Claims priority, application Japan, Dec. 16, 1969, 44/101,115 Int. Cl. G03c 5/32 U.S. Cl. 96-60 12 Claims ABSTRACT OF THE DISCLOSURE A single bleach-fixing solution for color photographic light-sensitive materials comprising a ferricyanide and a thiocyanate and containing at least one compound having an aldehyde group or a methylol group is disclosed.

BACKGROUND OF THE INVENTION (1) Field of the invention The present invention relates to an improved bleachfixing (blixing, solution in color photographic processings.

(2) Description of the prior art In general, the processings for color photographic materials include the steps of color development, stopping, first fixing, bleaching, second fixing, hardening, stabilizing, and the like, but such processings as they are usually practiced are simplified and the period of time for processing is shortened by conducting the stopping step and the first fixing step, the bleaching step and the second fixing step, or the second fixing step and the hardening step, in one bath. Further, such a technique is closely connected with the elements used for each light sensitive material.

The present invention provides an improved bleachfixing solution for the color photographic processings as described above.

Typical bleaching solutions for color photographic materials are a bleaching solution in which a water-soluble iron complex salt of ethylene diamine tetraacetic acid is used as the oxidizing agent and a bleaching solution in which a ferrocyanide is used as the oxidizing agent. The former case is advantageous in that bleach-fixing can be done easily with a single solution which combines the bleaching and fixing since the oxidizing agent is stable with a thiosulfate but the employment of the former type bleaching solution is accompanied by disadvantages due to the weak oxidizing power of the oxidizing agent such that when a type of coupler is used, the leuco compound formed by the color forming development can not be oxidized into the dye. It is known to use an additional oxidizing bath after applying such a bleach-fixing procedure for improving such disadvantages (see, for example, the specification of British Pat. No. 1,026,496), but such an approach necessitates the use of a number of processing baths complicating the processing. Also, various attempts are known in which various types of accelerators are added in the case of using the water-soluble iron complex salt of ethylene-diamine tetraacetic acid (see, for example, the specification of British Pat. Nos. 1,150,466 and 926,569), but such approaches are inferior in bleaching speed to the process in which a ferricyanide is used.

On the other hand, when a ferricyanide is used, the bleaching power is sufiiciently strong and the reduction in image quality by weak bleaching does not occur but since the oxidizing power is strong, it decomposes a thiosulfate when a thiosulfate is used as a fixing agent together with ferricyanide, which requires the separate use of the bleaching process and the fixing process. However, since the thiocyanate, dithiosuberic acid, and known mercapto compound, as described in the specification of U.S. Pat. Nos. 3,335,004 and 3,342,598, are stable when present together with a ferricyanide, a single solution type of bleach-fixing solution can be used.

SUMMARY OF THE INVENTION As the result of various investigations on single types of bleach-fixing solutions containing the ferricyanide (or the ferricyanide and ferrocyanide) and the thiocyanate as described above, it has been discovered that by adding a compound having an aldehyde group or a methylol group to the above solution, the advantageous characteristics shown below can be obtained.

(1) Bleaching, fixing and hardening can be done with a single solution. That is to say, since it can be processed without an additional hardening bath, one processing bath can be omitted. This, as a matter of course, gives the advantages that the processing steps can be simplified and the processing period of time can be shortened.

(2) The occurrence of physical damages, such as scratching of emulsion layer which can occur at the bleach-fixing procedure, can be prevented.

(3) The stability, and in particular the light fastness and the heat resistance of images, is improved.

(4) The reduction in color density or fading which can occur on ferro-type finishing of a light sensitive material containing a type of magenta coupler is prevented.

Moreover, the single bleach-fixing solution according to the present invention has the same bleaching power and bleaching speed as those of a conventional ferricyanidetype bleaching bath and in addition, the solution has the same hardening power and hardening speed as those of a conventional hardening bath. Also, the stability of the processing solution per se is better than the conventional bleaching bath, fixing bath and hardening bath.

DETAILED DESCRIPTION OF THE INVENTION The bleaching agent used in this invention is a ferricyanide or a combination of a ferricyanide and a ferrocyanide, e.g., an alkali metal salt such as the sodium, potassium or lithium salt and an ammonium salt. The fixing agent used in this invention is a thiocyanate (in which the associated counter ion is a positive ion other than an ion of Ag, Hg, Cu, and Au, for example, a positive ion such as the salt of NH K, Na, Ba, and the like). Also, as the water-soluble compound having an aldehyde group or a methylol group used in this invention, a compound represented by the following general Formula I R-CHO (I) wherein R represent a hydrogen atom, an alkyl group, an allyl group, an aryl group or-a heterocyclic residual group, in which each of the groups may be substituted, is preferably used.

Examples of compounds shown by the general Formula I which can be used in this invention are formaldehyde, paraformaldehyde, acetaldehyde, aldol, propiolaldehyde, acrolein, crotonaldehyde, salicylaldehyde, glyoxylic acid, mucochloric acid, mucobromic acid, furfural, diglycolaldehyde, and the like. The compound to be used in this invention can also include precursors of the above-described compounds.

Also, as the water-soluble compound, a compound represented by the following general Formula II OHC-R-CHO 11 wherein R represents a single bond, a divalent aliphatic group or a divalent aromatic group can be used.

Examples of compounds represented by the general Formula II are glyoxal, succinaldehyde, glutaraldehyde,

ot-methylglutaraldehyde, cyclopentane-dicarboxyaldehyde, and the dialdehydes described in the specification of British Pat. No. 1,102,001, for example, OHCCH OCH CHO and OHCCH NHCH CHO, and French Pat. No. 1,543,- 694, for example, 2,4-di-aldehyde phenol. Also, the compound to be used in this invention can include the precursors of the above-described compounds as shown, for example, in Japanese patent publication No. 27,570/ 64, for example 2,5-dialkoxy-tetrahydrofuran.

Furthermore, as the water-soluble compound to be used in this invention, compounds represented by the following general Formula III I R"CH OH (III) wherein R" represents an aliphatic group, an aromatic group or a heterocyclic group is preferably used.

Examples of compounds represented by the general Formula III are N-methylol urea, N,N-dimethylol urea, N-methylolmethylenebismonoethyl urea, N'-methylol- N,N-dimethylol urea, methylohydantoin, hydroxydimethylbiuret, trihydroxymethylbiuret, 2,2,6,6-tetramethylolcyclohexanol, methyloldicyandiamide, the compounds described in the specification of British Pat. No. 1,116,944, such as 3 hydroxy-2,2-dihydroxymethylpropionic acid, and 2 nitroethanol derivatives described in Japanese patent application No. 67,799/ 69, such as 2-nitro-2-methyl-1,3-propandiol.

It is astonishing that the reducing compounds shown by the above described compounds (I), (II), and (III) are stable in a bleach-fixing bath containing, a strongly oxidizing ferricyanide.

The amounts of the compounds to be used in the present invention are as shown in the following table.

From 2 glitter to tht maximum solubility.

From 1 g./liter to the maximum solubility.

Compound having an aldehyde group or a methylol group.

If necessary the single bleach-fixing solution of this invention can contain a buffering agent to establish the pH range desired or other subsidiary chemicals. Further, the stabilizing bath subsequent to the processing by the single bleach-fixing solution of this invention can be omitted or the stabilizing processing as described in the specification of British Pat. No. 1,092,258 can be applied after the processing by the single bleach-fixing solution of this invention.

The advantages of the single bleach-fixing solution of this invention are stated above but, in particular, formaldehyde and paraformaldehyde of the compounds shown by the general Formula I, the compounds shown by the general Formula II, and the Z-nitroethanol derivatives shown by the general Formula III are effective to obtain the advantages 1 to 4 mentioned above, While the other compounds are particularly effective to obtain the advantages 3 and 4 described above.

Examples of light sensitive materials to be processed by the single bleach-fixing solution of this invention are color photographic light sensitive materials containing the acetanilide-type yellow couplers as described in the specification of British Pat. No. 1,113,038 and U.S. Pat. No. 3,409,439; the pyrazolone-type magenta couplers as described in the specification of British Pat. No. 1,142,553 and US. Pat. No. 3,337,344; and the phenolic couplers as described in the specification of US. Pats. Nos. 2,423,730, 2,474,293 and 2,801,171 but the light sensitive materials to which the invention is applicable are not limited to these examples.

Now the experimental results typically obtained with the various improvements obtained by using the singlebath bleach-fixing and hardening solution of this invention are shown by the following examples although the invention is not to be interpreted as being limited thereby.

EXAMPLE 1 5 Color forming developing solution (pH 10.6)

Sodium metaborate g 25.0 Sodium sulfite g 2.0 Hydroxylamine (sulfate) g- 2.0 Potassium bromide g 0.5

6-nitrobenzimidazole (nitrate) g 0.02 Sodium hydroxide g 4.0 Benzyl alcohol ml.... 15.8 Diethylene glycol ml 20.0 N ethyl N B (methane sulfoneamideethyU- p-phenylene diamine (sulfate) g 8.0

Water added to make 1 liter.

Stop-fixing solution (pH 4.5)

Ammonium thiosulfate g 120.0

Sodium pyrosulfite g 20.0 Glacial acetic acid g 10.0 Water added to make 1 liter.

Bleaching solution (pH 7.2)

Potassium nitrate g 25.0 Ferricyanide g 20.0 Potassium bromide g 8.0 Boric acid g 5.0

Borax g 2.5

Water added to make 1 liter.

Bleach-fixing solution (pH 7.2)

Solution-1 Solution-2 Sodium thiocyanate, g 32. 0 32. 0 Potassium nitrate, g 25. 0 25. 0 Ferricyanide, g-" 20. 0 20. 0 Boric acid, g 5. 0 5. 0 Borax, g 2. 5 2. 5 Formalin (35-40%), ml- 40. 0

Water Added to make 1 liter.

Hardening-fixing solution (pH 9.5

Ammonium thiosulfate g 120.0

Sodium sulfite g 5.0 Boric acid g 2.5 Formalin (35-40%) ml 40.0 Water added to make 1 liter.

Hardening solution (pH 9.5)

00 Sodium metaborate g 0.5 Formalin (35-40%) ml 40.0 Water added to make 1 liter.

Buffering bath (pl-I 5.0)

Zinc sulfate g 10,0 Tartaric acid g 10.0 Sodium metaborate g 20.0 Water added to make 1 liter.

A color photographic paper prepared by coating a baryta-coated paper with a blue-sensitive silver iodobromide emulsion layer containing benzoylaceto-Z-chloro-S- dodecyloxycarbonyl anilide as a yellow coupler, a gelatin intermediate layer, a green-sensitive silver chlorobromide emulsion layer containing l-phenyl-3-[3-(N-butylcaprylamidopropionamido)j-5-pyrazolone as a magenta coupler, a gelatin intermediate layer, a red-sensitive silver chlorobromide emulsion layer containing 1-hydroxy-2-[3-(2,4- t-amylphenoxy)propyl]-naphthamide as a cyan coupler, and a protective gelatin layer successively was exposed and then subjected to the following processings at 30 C.

PROCESS A The exposed color photographic paper was subjected to color development for 7 minutes, top-fixing for 2 minutes, washing for 2 minutes, bleaching for 2 minutes, washing for 2 minutes, hardening-fixing for 2 minutes, washing for 4 minutes, and buffering for 2 minutes.

PROCESS B The exposed color photographic paper was subjected to color development for 7 minutes, stop-fixing for 2 minutes, washing for 2 minutes, bleaching-fixing using the bleach-fixing solution-1 for 2 minutes, washing for 2 minutes, hardening for 2 minutes, washing for 4 minutes, and buffering for 2 minutes.

PROCESS C The exposed color photographic paper was subjected to color development for 7 minutes, stop-fixing for 2 minutes, washing for 2 minutes, bleach-fixing using bleach-fixing solution-l for 2 minutes, washing for 4 minutes, and butfering for 2 minutes.

PROCESS D The exposed color photographic paper was subjected to color development for 7 minutes, stop-fixing for 2 minutes, washing for 2 minutes, bleach-fixing using bleachfixing solution-2 for 2 minutes, washing for 4 minutes, and buffering for 2 minutes.

After the processings were finished, the color paper was subjected to ferrotype drying at 80 C. and the following Key.O=No layer melted, A=S1ightly melted, X =Entirely melted.

As is clear from the experimental results set forth above, in Process C in which the conventional bleach-fixing solution-1 was used and the hardening bath was omitted, the time required for ferrotype drying was longer and the melting of emulsion layer was very severe. On the other hand, in the case of processing using the bleach-fixing solution-2 of this invention (Process D), the time required for ferrotype drying was the same as that in the Process A in which the conventional bleaching bath and the conventional hardening-fixing bath were employed and, also, almost no melting of the emulsion layer was observed. Accordingly, the hardening bath and the washing accompanied by the hardening processing is unnecessary. Therefore, it is possible to omit two processing baths, which results in a simplification of the photographic processings and a shortening in the processing period of time.

The period of time required for finishing the bleaching was almost the same in Processes A-D, as is shown in the following table.

Process A B C D Process A B C D Time required for finishing bleching seconds 60 62 63 60 With respect to the color papers processed by Process A-D, respectively (bleach-fixing for 2 minutes), the stability of the images obtained was tested under the conditions shown in the following table.

The fading ratio is the ratio of the color density reduced during the test to the initial color density.

As is clear from the experimental results, in Process C in which the bleach-fixing solution having conventional composition was used and the hardening bath was omitted, the stability of the image to heat and light was reduced greatly, while in Process D in which the improved bleachfixing solution of this invention was employed, the stability of the image to light and heat was excellent.

After processing 4 m. /liter of the color photographic paper by the bleaching solution or the bleach-fixing solution used in this experiment, the solution was allowed to stand for 3 months but each solution was similarly stable. On the other hand, a bleach-fixing solution in which a thiosulfate was used as a fixing agent formed a considerable amount of precipitate within 15 minutes, which made it impossible to use the solution further.

As anticipated as a matter of course, when a film base was employed instead of the baryta-coated paper, similarly excellent results were obtained with respect to the bleaching speed and the stability of image.

EXAMPLE 2 After exposing and processing the color developing solution and the stop-fixing solution as shown in Example I, the color photographic paper as shown in Example 1 was processed with a bleach-fixing solution having the following composition:

Water added to make 1 liter.

The additive is shown in the following table, in which the melting conditions of the emulsion layer by ferrotype drying, the time required for finishing the ferrotype drying and also the time required for finishing the bleaching are also shown.

Melting Bleachin Additive condition Drying time time g Paraiormaldehyde 4 min 60 sec. Succmaldehyde 3 min. and 55 see- 62 sec. Glutaraldehyde. -A 4 sec.

mm 2-nitro- 2-methyl-1,3-pro- 3 min. and 55 sec 60 sec.

pandiol.

On comparing the experimental results and the results shown in the table of Example 1, it is clear that in using each of the bleach-fixing solutions of this invention, the ferrotype drying time, the state of emulsion layer, and the bleaching speed were almost the same as those in Process A in which the known bleaching bath and the known hardening-fixing bath were employed and further in using the bleach-fixing solution of this invention, one processing bath and one washing bath could be omitted.

The results of testing the stability of the image and the stability of the solution per se were almost the same as those in Example 1.

EXAMPLE 3 The color photographic paper subjected to color development, stop-fixing and washing as shown in Example 1 was processed for 2 minutes using the bleach-fixing solution as shown in Example 2 except that the additive was replaced with the additives shown in the following table and then subjected to washing and buifering.

In the following table are shown the results of testing the ferrotype fading of the magenta color image (ratio to natural drying) formed by subjecting the color photographic paper processed above to ferrotype drying at C. and also the results of conducting the same experiment for testing the stability of the magenta color image to heat and light as in Example 1. The numerical values in the table are fading ratios at a density of 0.5.

Exposure Ferrotype for 5 days to Stored for drying at fluorescent 7 days at Additive (3 g.,lliter oi bleach- 80 C. lamp (10 76.7 C fixing solution) (percent) lux) (percent) Aoetaldehyde 8 2 Acrolein O 10 3 Crotonaldehyde 0 10 3 Salicylaldehyde. 0 1O 4 Cinnamaldehyde. 2 12 Glyoxylie acid 2 11 4 Mucochloric acid-. 1 12 5 0 3 Methylolhydantoin l) *J 2 Hydroxymethylbiurct. 1 12 -'l Methylol dicyandiamid l) 10 2 None (process 0) 8t] 5t) From these experimental results, it is clear that the improved bleach-fixing solution of this invention was greatly eifective for the prevention of fading to ferrotype drying and fading to heat and light.

EXAMPLE 4 A color photographic film prepared by coating on a film support a blue-sensitive silver iodobromide emulsion layer containing the yellow coupler shown in Example 1, an intermediate gelatin layer, a red-sensitive silver chlorobromide emulsion layer containing the cyan coupler shown in Example 1, an intermediate gelatin layer, a green-sensitive silver chlorobromide emulsion layer containing the magenta coupler shown in Example 1 and, then a protective gelatin layer, successively, was subjected to color development and stop-fixing as in Example 1 and then processed using the bleach-fixing solution shown in the following table. In addition, the pH of the solution was adjusted to 7.0 using an aqueous NaOH solution.

Water No'rE.- (3)-(8) designates bleach-fixing solutions 3 to 8.

In this case, the time required for the bleach fixing and the stability of the magenta color image are as shown in the following table.

Bleaching time, see 47 49 47 50 55 50 Exposure for 5 days to a fluorescent lamp (10* lux), percent 12 12 10 8 25 Stored for 7 days at 76.7 C. under low humidity, percent 3 4 3 3 2 45 From the experimental results shown above, it is clear that the bleach-fixing solution of this invention gives an image having an excellent stability with the same bleaching speed as that in the known bleach-fixing solution (bleaching fixing solution 8).

The fading prevention eifect of the magenta image to ferrotype fading in processing the color photographic paper as shown in Example 1 by each of the bleach-fixing solutions 3-7 was same as in Example 3. Also, the emulsion layer condition and period of time for ferrotype drying were almost the same as the case of Process D in Example 1.

What is claimed is:

1. A single bleach-fixing solution for color photographic light sensitive materials comprising an alkali metal or ammonium ferricyanide and an alkali metal, ammonium or barium thiocyanate, characterized in that said bleach-fixing solution contains at least one compound having an aldehyde group or a methylol group.

2. The bleach-fixing solution as claimed in claim 1, wherein said compound having an aldehyde group or a methylol group is a compound represented by the following general formula R-CHO wherein R is selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group, an allyl group and a heterocyclic residual group, and wherein said group may be substituted.

3. The single bleach-fixing solution as claimed in claim 1, wherein said compound having an aldehyde group or a methylol group is a compound represented by the following general formula wherein R is selected from the group consisting of a direct bond, a divalent aliphatic group and a divalent aromatic group.

4. The single bleach-fixing solution as claimed in claim 1, wherein said compound having an aldehyde group or a methylol group is a compound represented by the following general formula wherein R" is selected from the group consisting of an aliphatic group, an aromatic group and a heterocyclic residual group.

5. A single bleaeh-fixing solution for color photographic light sensitive materials comprising an alkali metal or ammonium ferricyanide, an alkali metal or ammonium ferrocyanide and an alkali metal, ammonium or barium thiocyanate, characterized in that said bleach-fixing solution contains at least one compound having an aldehyde group or a. methylol group.

6. The single bleach-fixing solution as claimed in claim 5, wherein said compound having an aldehyde group or a methylol group is a compound represented by the following general formula R-CHO wherein R is selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group, an allyl group, and a heterocyclic group, and wherein said group may be substituted.

7. The single bleach-fixing solution as claimed in claim 5, wherein said compound having an aldehyde group or a methylol group is a compound represented by the following general formula wherein R is selected from the group consisting of a direct bond, a divalent aliphatic group and a divalent aromatic group.

8. The single bleach-fixing solution as claimed in claim 5, wherein said compound having an aldehyde group or a methylol group is a compound represented by the following general formula wherein R" is selected from the group consisting of an aliphatic group, an aromatic group and a heterocyclic residual group.

9. The single bleach-fixing solution as claimed in claimv 1, wherein said compound having an aldehyde group or methylol group is formaldehyde.

10. The single bleach-fixing solution as claimed in claim 1, wherein said ferricyanide is potassium ferricyanide, wherein said thiocyanate is sodium thiocyanate and wherein said compound having an aldehyde or methylol group is formaldehyde.

11. The single bleach-fixing solution as claimed in claim 1, wherein said ferricyanide is potassium ferricyanide, wherein said thiocyanate is potassium thiocyanate and wherein said compound having an aldehyde or methylol group is formaldehyde.

12. The single bleach-mixing solution as claimed in claim 1, wherein said ferricyanide is potassium ferricyanide, wherein said thiocyanate is ammonium thiocyanate, and wherein said compound having an aldehyde or methylol group is formaldehyde.

References Cited UNITED STATES PATENTS 3/ 1967 Wrisley et al 96 22 5/1967 Bard 96-60 US. Cl. X.R. 

